Knock-off mechanism



Aug. 6, 1940.

H. B. LANDRUM KNO CK-OFF MECHANISM Filed Jan. 25, 1940 2 Sheets-Sheet l awuam bo'n HQ wan;

Aug. 6, 1940. H. B. LANDRUM KNOCKLOFF MECHANISM Filed Jan. 25, 1940 2 Sheets-Sheet 2 m awe/whom fiB.L an dru m war/wan Patented Aug. 6, 1940 UNITED STATES 2,210,172 KNOCK-OFF MECHANISM Harvey 'B. Landrum, Pampa, Tex.

Application January 25, 1940, Serial No. 315,583

8 Claims.

by getting his hands or clothing caught in any of the moving parts of the mechanism.

Another object of the invention is to provide a knock-off mechanism which includes a pair of detachably connected reciprocable units enclosed within a stationary housing, with means for disconnecting such units while the mechanism is in v operaiton or connecting the same together, wherein the major portion of such connected units and the means for connecting and disconnecting the same isenclosed in said housing in such manner that the moving parts are protected against the entrance of dirt and against interference with their operation by the entrance of snow or ice and wherein the said means are readily operable from outside the housing in such manner that all danger of the operator becoming entangled with the moving parts and injured thereby is avoided.

Still another object is to provide in a knockofi mechanism of the character stated wherein there is employed a reciprocating unit made up 5 of two telescoping parts, a latching means for holding such units in longitudinally adjusted operative relation, a second latching means, which is free of connection with the units when the first latching means is in operative position 40 and which is employed for releasing the first latching means whereby one of the units is made idle while the other one continues to reciprocate, together with a novel elevator mechanism designed to automatically disconnect the secondmentioned latching means from the said one of the units after the units are operativelycoupled together by the throwing in of the first-men tioned latching means to operative or elementcoupling position. 1

The invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming part of thisspecification,

with the understanding, however, that the in-' vention is not to be confined to any'strict con-- formity' with the showing of the drawings but may be changed or modified so long as such.

changes or modifications mark no material de-- parture from the salient features of the invention as expressed in the appended claims. 5 J.

In the drawings: I 5 a Fig. 1 is a view in horizontal longitudinal sec-f tion through thehousing only ot-one. half ofthe knock-off mechanism embodying the present invention. 1 v I Fig, 1 is a sectional View corresponding to Fig. 1 and extending through the other half-of the mechanism. I

Fig. 2 is a vertical longitudinal section through the entire half of themechanism shown in Fig. 1-. 1 5

Fig. 2 is a vertical longitudinal section corresponding to Fig. 2-and-extending through the other half of themechanism.

Fig. 3 is a transverse section on the line 3-'-3 Of Fig. 1. I Fig. 4 is a sectional view taken on the line 4-4 ofFig.2 1 Referring now more particularly to the drawings, the numerals l and 2 designatefixed supporting posts upon which the present knock-oft mechanism is mounted,'the post I being coupled by a tie rod 3 with a suitable fixed structure disposed rearwardly of'the mechanism','such as the' structure housing the power mechanism, not shown, whereby a bracing of the mechanism sup- 301 port'against thrusts imparted by moving parts of the mechanism, is obtained. The numeral 4 designates a relatively long stationary housing which, while it may be of any suitable cross-sectional design, is here illustrated as being of tubular form. This housing extends across and is supported upon and secured to the posts I and 2. At one end of the housing 4 there is secured within the housing a sectional bearing block 5 having a central passage 6' therethrough which is coaxial with the housing. Sections of this block are adjustablyheld in position by stud screws 1. The end of the housing in which the bearing block 5 is disposed will be referred to as the rear end of the housing and-of the mechanism, as this end of the housing is'adjacent the power source, not shown,'by which the mecha-- nism is operated. Intermediate its ends the housing encloses a second or intermediate bear ing block 8 of the same form as the block 5. and 50 having its sections held in place by the screws 9,: this intermediate block having an axial passage or bore I0 therethrough. Between the'bearing' blocks 5 and 6 or in the rear half of thehousing;

' there is formed in the wall of the housing the-top; 5.;

1 the opening I opening over which is disposed a cover or door I2, which may be hingedly attached to one side of the housing by the longitudinally spaced hinge ears l3, carried by the door and coacting with the hinge ears l4 carried by the housing. A suitable means may be provided for securing the door in closed position as by the provision at the opposite side of the housing from the hinge ears l3l4 of a similar pair of ears |5-|6, one of which may be carried by the housing and the other by the door, the last-mentioned ears forming a look through which a securing pin I! is passed;

At the forward end of the housing, the upper half of the housing is cut away, as indicated at H, and the lower part of the housing supports a rub block I8, the upper surface of which is transversely recessed for the purpose hereinafter stated.

The numeral l9 designates a reciprocating unit of the lmock-ofi mechanism. This unit comprises an elongated tubular portion 29 which extends longitudinally of the housing through the bearing blocks 5 and 8, and the rod portion 2| which extends into the tubular portion 2|) from the forward end of the housing and rests upon the rub block l8 in the transverse top recess thereof, as shown in Fig. 2

The tube 20 upon the outer rear end thereof carries a coupling head 22 which is provided with a yoke 23 and into the yoke of this head extends the head portion 24 of a power rod 25 which is connected with a suitable source of power designed to impart reciprocatory motion to the rod. The head 24 is secured in the yoke 23 by a removable swivel pin 26 which is provided with a suitable grease coupling 27 by means of which lubricant may be injected by a grease gun through suitable greasing grooves or channels, not shown, for lubricating the surface of the pin and the surfaces of the swivel 23 and head 24 with which it is in contact.

The tube 2|) is provided with a relatively short top opening 28 in the portion of the tube lying beneath the housing opening H and this opening 28 is disposed adjacent the forward end of the housing opening I i when the reciprocating unit l9 is at the limit of its forward movement and upon the rearward movement of the unit I9, the opening moves to a position adjacent the rear end of Thus, in the operation of the mechanism the opening 28 of the tube 20 always remains within the limits of the space between the ends of the opening I l.

Secured to the under side of the tube 20 adjacent the opening 28 is a pivot ear 29. Straddling the portion of the tube 20 adjacent the opening 28 are the side or leg members 36 which are coupled together at one end by adog 3| which is of substantially triangular cross-section as shown in Fig. 2, and which extends across the top of the rod 2|, engaging this rod through the opening 28. The lower ends of the legs 3|] of this unit which constitutes a latch between the rod 2| and tube 20 are coupled together by the pivot pin 32 which passes through the ear 29. The top of the dog 3| has connected therewith one end of a contractile spring 33, the other end of which spring is connected'as indicated at 34, with the tube 20. This spring normally tends to pull the dog upwardly away from the rod 2!. The rod 2|, which is of circular cross-section, has at spaced intervals longitudinally, the encircling notches 35, each of which has a vertical face which is directed forwardly of the mechanism and which is designed to be engaged by a face of the dog 3|, and an upwardly and forwardly inclined face 36, which functions as a cam to lift the dog 3| out of the notch under certain conditions of operation of the mechanism. At the forward end of the rod 2|, a coupling unit 31 is provided for connecting the rod with a pull rod 38 which leads to the mechanism which is driven from the power source through the knock-01f mechanism under consideration.

Adjacent the rear end of the housing 4, there is pivotally supported upon ears 39 secured to the housing beneath the rod 2|, the leg members 40 of the second latching unit, the'upper ends of which leg members are connected by the dog 4| which extends transversely of the rod 2|. The legs 40 straddle the rod and swing upwardly upon the pivot pin 42 by which their lower ends are connected with the ears 39, in the open space H of the housing. Pivotally coupled with the dog 4| is a pull rod 43 which extends rearwardly along the top and outside of the housing through a guide 44. The rear end of this pull rod is provided with a handle 45 by means of which the rod may be readily grasped and actuated for the purpose of raising or lowering the dog 4|.

As will be readily understood, the dog 4| is designed for selective engagement in the notches 35 of the rod 2| of the reciprocating unit and when so engaged, it will hold the rod against forward movement but will not affect the movement of the tube 20. The operation of this dog in association with dog 3| will be hereinafter fully described.

The numeral 46 generally designates an elevator unit which is provided to effect the automatic disengagement of the dog 4| from a notch 35. This elevator comprises a suitable body having an inclined edge or face 41, the lower end of which face or edge is nearerthe dog 4| than the higher end. The body providing this inclined or camming edge 41 is here shown as being in the form of a triangular frame 48, but it will be readily apparent that a solid plate member may be employed, if desired, or any other suitable means which will provide a sharply inclined camming surface of a width which will permit it to pass between legs 4!) connecting the dog 4| so as to ride under the lower side of the dog 4| to lift it from a notch with which it may be engaged.

The frame 48 is secured upon a sleeve 49 which encircles and has free rotary movement on the forward end of the rod 2|, the sleeve being held against longitudinal movement by the provision of a hook 5|) engaging over a collar 5| which surrounds and is secured to the rod. The member 48 is maintained in the desired upright or vertical position by the provision of a balance weight 52 secured to the sleeve 49 upon the opposite side thereof from the member 48. By this means, the camming edge 4'! is always maintained in a desired position to pass beneath the dog 4|. This construction also permits, together with the annular notches 35 which encircle the rod 2!, the rotation of the rod within the tube 20, thereby providing for turning of the pull rod 38 which will prevent the twisting of cables or other units which may be employed between the knock-off mechanism and a drill tool or other piece of well machinery in the event that such drill tool or other machine tends to turn while in operation.

In the operation of the present knock-off mechanism, the tube 20 is coupled with the rod 2| by the engagement of the dog 3| in one of the notches 35 in order to effect transmission of re- 7 the actuating bar 54.

ciprocal motion from the power rod 25 to the pull rod 38. It will be understood that upon rear ward movement of the rod 25 under the action of the power source, the dog 3| will beheld in frictional engagement with the vertical face of the notch in which it is engagedby reason of the tendency of the rod and tube to pull apart and on forward movement of the reciprocating" unit, the same locking action is maintained between the dog and the vertical face of the engagednotch by the same action resulting from the pull of the drill unit or other device coupled with the pull rod 38 and the dragging of the power rod 25. During such operation, the second-mentioned dog which might be referred to as the uncoupling dog, will be raised above the rod 2| and free from contact therewith, as shown in Fig. 2 The tube 20 slides through the hardwood bearing blocks 5 and 8 during all reciprocatory motion of the unit l9.

When it is desired to release the well machinery or stop its motion without interrupting the operation of the power machine which reciprocates the power rod 25, this is effected by the lowering of the releasing dog 4| through the medium of the hand rod 43tuntil such dog engages in a notch 35 of the rod 2 I. This will hold the rod 2| against forward movement and when during this holding period the tube 20 is moved forwardly, it will be at once apparent that the dog 3| will be shifted out of the notch in which it was engaged and the spring 33 will at once take control and swing the dog upwardly away from the rod 2|. This dog together with the tube 20 may then reciprocate freely on the rod 2| but the rod will be held stationary.

In order that re-engagement of the latching dog 3| with the rod 2| may be effected without danger to the operator of the mechanism, one of the legs 30 is provided with a laterally extending pin 53 for engagement by an oscillatable control bar 54. This control bar is relatively long, being of a length substantially equaling the length of the opening I and at its ends it has laterally extending legs 55 which project through openings 56 in the wall of the housing 4. Between the projecting legs 55, the wall of the housing carries a pair of bearing eyes 51 through which extend the rod shaft 58 and the ends of this shaft are coupled, as indicated at 59, with the ends or legs 55 of The rock shaft 58 has coupled with it an outwardly extending control lever 60. The re-engagement of the latching dog 3| with the rod 2| is effected as follows: When the latching dog is out of engagement with the rod 2|, it will be in a raised position as previously stated and at the time that it is raised by the spring 33, the pin 53 will force the actuating bar 54 upwardly. By raising the lever 60, the bar 54 will force the pin 53 and consequently the dog 3| downwardly into engagement with the rod 2|. Since the bar 54 extends lengthwise of the reciprocating tube 20 but is itself held against longitudinal movement, it will be readily apparent that this action may be safely carried out as the pin 53 will slide along the under side of the actuating bar. On its forward movement with the tube 20, the dog 3| will slide over the notches 35 but when the tube starts upon a rearward movement, the dog 3| will engage in one of the notches, thus coupling or looking the bar 2| and tube 20 together. The dog 4| is still in down position, engaging the bar 2| and, therefore, if it remained in this position when the reciprocating unit again started its forward movement, it wouldengage one of the notches 35 and again uncouple the out by first engaging the dog 4| in a notch 35 to effect knocking off the connection. When this is done as previously stated, the dog 3| will be released. After this, the dog 3| will be reengaged one or more notches back from where it was originally engaged or from its former operating position, and the dog 4| is then manually shifted to. detach it from connection with the rod 2|, this manual operation being necessary since the elevator 46 will not come back far enough to automatically disengage the dog 4|.

-By continuing or repeating this operation, the

well can be let down completely and the rod line made. slack.

From the foregoing, it will be readily apparent that there has been provided in the mechanism herein described, a structure which can be controlled easily and without danger to the operator and since the parts which the operator has to handle in order to effect the coupling and uncoupling of the parts of the reciprocating unit do not in themselves move with the reciprocating unit, there is no possibility of the operator becoming injured. All of the movable and reciprocating parts of the mechanism are also fully protected or housed so that the possibility of sand and dirt getting into the tube or interfering with the proper operation of the latching dog 3|, as well as the possibility of the operation of the parts being interfered with or stopped by ice or snow or freezing water, is entirely eliminated.

What is claimed is:

1. A knock-off mechanism for connection between a reciprocal power element and an actuated element,. comprising an elongated reciprocable unit, comprising two elements one of which is sli'dably engaged with the other, means for coupling an end of one element with the power element, means for coupling the remote end of the other element with the actuated element, a shiftable latching member carried by the said one element for detachable connection with .the other element, the said other element being constructed to facilitate such detachable engagement of the latching element therewith at a plurality of points arranged longitudinally thereof, resilient means normally urging movement of the latching element away from the said other one of the reciprocating elements, a closed housing completely enclosing saidlatching member and resilient means, a second latching element partially enclosed in said housing and having a fixed support relative tothe reciprocating unit and adapted to be moved into and out of engagement with the said other one of the reciprocating elements, and'means operatively coupled with the first-mentioned latching element for effecting its movement against said resilient means into engagement with the said other one of the recip rocable elements, from outside said housing.

2. A knock-off mechanism for positioning between a reciprocating power body and an actuated body, comprising an elongated reciprocable unit made up of two'telescopically joined elements, means for connecting the outer end of one of the two joined elements with the power body, means for coupling the outer end of the other one of the two joined elements with the actuated body, a plurality of means spaced longitudinally along'said other one of the connected elements facilitating engagement of a dog therewith, a latching dog carried by the said one of the joined elements and movable thereon for engagement with one of the third-mentioned means, a spring member normally urging movement of said dog away from. the third-mentioned means, a second dog having a fixed position with respect to the reciprocating unit and movable for selective engagement with said third-mentioned means, means carried by the said other one of the joined elements which is movable into engagement with the second-mentioned dog to disengage the same from the third-mentioned means upon movement of the joined elements together, and means for shifting the first-mentioned dog into engagement with one of the third-mentioned means against the action of said spring, comprising a pin operatively coupled with the first-mentioned dog, a bar extending longitudinally of the reciprocal unit and engaging over said pin, supporting means facilitating the rocking of the bar on an axis extending longitudinally of the reciprocable unit, and means facilitating the rocking of the bar on said axis.

3. A knock-off mechanism for connection between a reciprocable power element and an actuated element, comprising an elongated housing, a plurality of bearing blocks within the housing and spaced longitudinally therein, an elongated longitudinally reciprocable unit extending longitudinally through the housing, said unit comprising a tubular portion supported by certain of said bearings and a rod having an end extended into the tubular portion, means at the outer end of the tubular portion for connection with said power element, means at the outer end of said rod for connection with the actuated element, a dog oscillatably carried on the tubular element and completely enclosed within the housing and movable through an opening in the tubular element for engagement with said rod, means facilitating the coupling of the dog with the rod at selected points spaced longitudinally of the rod, a second dog supported by and within the housing and movable for selective engagement with said means, and means facilitating the manual actuation of either of said dogs from outside said housing.

4. A knock-off mechanism for connection between a reciprocable power element and an actuated element, comprising an elongated housing, a plurality of bearing blocks within the housing and spaced longitudinally therein, an elongated longitudinally reciprocable unit extending longitudinally through the housing, said unit comprising a tubular portion supported by certain of said bearings and a rod having an end extended into the tubular portion, means at the outer end of the tubular portion for connection with said power element, means at the outer end of said rod for connection with the actuated element, a dog oscillatably carried on the tubular element and completely enclosed within the housing and movable through an opening in the tubular element for engagement with said rod, means facilitating the coupling of the dog with the rod at selected points spaced longitudinally of the rod, a second dog supported by and within. the housing and movable for selective engagement with said means, means facilitating the manual actuation of either of said dogs from outside said housing, and an elevator unit supported upon said rod between the second-mentioned dog and the said outer end of the rod and formed for engagement with the second-mentioned dog when the latter is in operative engagement with the rod to lift said dog from such engagement when the rod and tubular element are coupled by the first dog and shifted together.

5. A knock-off mechanism for connection between a reciprocable power element and an actuated element, comprising an elongated housing, a plurality of bearing blocks within the housing and spaced longitudinally therein, an elongated longitudinally reciprocable unit extending longitudinally through the housing, said unit comprising a tubular portion supported by certain of said bearings and a rod having an end extended into the tubular portion, means at the outer end of the tubular portion for connection with said powerelement, means at the outer end of said rod for connection with the actuated element, a dog oscillatably carried onthe tubular portion and completely enclosed within the housing and movable through an opening in the tubular portion for engagement with said rod, means facilitating the coupling of the dog with the rod at selected points spaced longitudinally of the rod, a second dog supported by and within the housing and movable for selective engagement with said last-mentioned means, means facilitating the manual actuation of either of said dogs from outside said housing, a spring member coupling the first-mentioned dog with the tubular portion and normally urging such dog to move away from the rod, the said means for manually actuating the first dog comprising a pin member coupled with the dog and projecting laterally with respect to the tubular portion, a rock shaft extending longitudinally of and supported by the housing for oscillation on its long axis, a rod extending longitudinally of the shaft within the housing and secured to the shaft to be oscillated in a vertical path, the lastmentioned rod being operatively coupled with said pin, and means for rocking said shaft and the last-mentioned rod to. effect depression of the pin and the adjacent dog.

6. A knock-01f mechanism for connection between a reciprocable power element and an actuated element, comprising an elongated horizontally disposed housing, a series of bearing members longitudinally spaced within the housing, an elongated reciprocable unit extending longitudinally through the housing and comprising a tubular element slidably supported by certain of the bearing members and a rod of circular cross-section having an end slidably extended into the tubular element and slidably supported upon a bearing member, said rod having a plurality of encircling notches spaced longitudinally thereof, means at the outer end of the tubular element for connecting the same with the reciprocable power element, means at the outer end of the rod for connecting the same with the actuated element, said tubular element having an opening cut therein, a dog member oscillatably supported by the tubular element adjacent said opening for extension therethrough for engagement with a notch, resilient means normally urging movement of the dog away from the rod, a second dog supported for rocking movement within and by the housing for selective engagement with a notch of said rod, independently operable means for eifecting manual actuation of said dogs with respect to the rod, and means for automatically detaching the second-mentioned dog from engagement with the rod, comprising a camming member disposed between the secondmentioned dog and the said outer end of the rod arranged to lift the adjacent dog from engagement with the notched rod when moved with the notched rod toward the dog, and means supporting the camming member from the notched rod.

'7. A knock-off mechanism for connection between a reciprocable power element and an actuated element, comprising an elongated horizontally disposed housing, a series of bearing members longitudinally spaced within the housing, an elongated reciprocable unit extending longitudinally through the housing and comprising a tubular element slidably supported by certain of the bearing members and a rod of circular cross-section having an end slidably extended into the tubular element and slidably supported upon a bearing member, said rod having a plurality of encircling notches spaced longitudinally thereof, means at the outer end of the tubular element for connecting the same with the reciprocable power element, means at the outer end of the rod for connecting the same with the actuated element, said tubular element having an opening out therein, a dog member oscillatably supported by the tubular element adjacent said opening for extension therethrough for engagement with a notch, resilient means norm-ally urging movement of the dog away from the rod, a second dog supported for rocking movement within and by the housing for selective engagement with a notch of said rod, independently operable means for effecting manual actuation'of said dogs with respect to the rod, means for automatically detaching the second-mentioned dog from engagement with the rod, comprising a camming member disposed between the secondmentioned dog and the said outer end of the rod arranged to lift the adjacent dog from engagement with the notched rod when moved 'with the notched rod toward the dog, means supporting the camming member from the notched rod, and a sleeve encircling the notched bar and supporting said camming member, the sleeve being freely turnable about the notched rod, and a counterbalance weight connected with the under part of the sleeve to maintain the camming member in upright position.

8. A knock-oil mechanism for connection between a reciprocable power element and an actuated element, comprising an elongated horizontally disposed housing, a series of bearing members longitudinally spaced within the housing, an elongated reciprocable unit extending longitudinally through the housing and comprising a tubular element slidably supported by certain of the bearing members and a rod of circular cross-section having an end slidably extended into the tubular element and slidably supported upon a bearing member, said rod having a plurality of encircling notches spaced longitudinally thereof, means at the outer end of the tubular element for connecting the same with the reciprocable power element, means at the outer end of the rod for connecting the same with the actuated element, said tubular element having an opening cut therein, a dog member oscillatably supported by the tubular element adjacent said opening for extension therethrough for engagement with a notch, resilient means normally urging movement of the dog away from the rod, a second dog supported for rocking movement within and by the housing for selective engagement with a notch of said rod, independently operable means for effecting manual actuation of said dogs with respect to the rod, means for automatically detaching the second-mentioned dog from engagement with the rod, comprising a camming member disposed between the secondmentioned dog and the said outer end of the rod arranged to lift the adjacent dog from engagement with the notched rod when moved with the notched rod toward the dog, means supporting the camming member from the notched red, the said manual control means for the firstmentioned dog, comprising a bar member disposed within the housing longitudinally of the reciprocating unit, means supporting the bar member for rocking movement on an axis extending longitudinally of said unit, the length of the bar member being slightly greater than the length of the path of movement of the firstmentioned dog with the tubular element, a pin member connected with the first-mentioned dog and extending across and engaged by said bar member, and means facilitating the rocking of the bar member on the said axis from outside the housing.

HARVEY B. LANDRUM. 

